This wild creation from the shop of Straight Up Racing is a lot of things–but mostly it's awesome. The recent, one-off build is a home-fabricated creation set to run in the monster truck circuit.

For many, the ascension to greatness is a strategic, pain-staking process. But for a select few individuals, it’s just the natural progression of things. Bill Payne of Straight Up Racing is one of the latter.

Based on an M5 Personnel Carrier, Major Payne was stripped down to the treads, dropping almost 12,000 pounds of steel in the process.

“It was just a right place at the right time kind of thing,” Bill says of Straight Up Racing’s origins. “I was always into the fab work and back in 2003 I was building a Jeep for a guy and he said, “Hey I’m thinking about getting a monster truck – would you take care of it and drive it when I don’t want to drive it?” I think I was 21 years old, and it didn’t take much convincing.”

Bill says that his client eventually lost interest in the truck, which provided a new opportunity for him. “I ended up buying it,” he says. “I begged and pleaded with promoters all over the country to get this thing out there. When I first started, I’d go from Washington to Texas, to New Jersey, to Alabama, etc., and any winnings I would make I’d invest straight back into the monster truck. It went from being a two-truck team to four, to six, and just kept going. Our team grew so fast because people like what we’re doing and the work we put into the show. You can always tell who’s in it for the money and who is in it because they love it. The people deserve to have a good show.”

Powering the beast is a big-block Chevy with a JE pistons, AFR cylinder heads, and a Weiand 8-71 blower. It's fed on injected alcohol and is estimated to produce 1,100-1,200hp.

These days Straight Up Racing provides its own all-inclusive traveling monster truck tour. “I have a few trucks that are built as stunt trucks – shorter wheelbase, they can do the tricks really well,” he explains. “Then the rest are more of a standard monster truck chassis that we use for racing.”

But Straight Up Racing’s latest project, Major Payne, is cut from a different cloth entirely. “Our main focus is our own tours now, where we just bring in our entire show,” Bill tells us. “We always want to bring in something new, and that’s where the tank comes into play.”

In order to move the engine to the front, the rotation of the driveshaft needed to be reversed. Originally, a custom reverser box was designed from steel (left). Later, a lighter, aluminum version was machined (right).

Bill says that tanks were popular back in the ‘80s and ‘90s, but the technology to make them viable for use in stunt exhibitions wasn’t really there yet. “They were hurting a lot of people – those things were 18,000 pounds with no suspension, and they were jumping them like a monster truck. I didn’t want to hurt myself doing that – I want to be able to do this when I’m 80 years old.”

With that in mind, Bill set to work building a tank that could work for the show long-term. He selected an M5 personnel carrier for the job. “The tank is actually going backwards,” he says. “My idea was that it had to be able to pivot on the back idler and wheelie on that back sprocket. That way I can go out there and just start rippin’ some wheelies, hit some jumps, and it’s still safe while doing lots of cool stuff.”

A Powerglide transmission replaced the original Allison unit and connects to the custom reverser box.

These days the M5’s setup is a far cry from where it was when it served in the military. “The only things that are left from its days as a personnel carrier are the tracks, the suspension, and the drive axle on the back,” he says. “Everything else has been removed – all the armor, the skid plates, the tub of the tank – everything was cut off. It got lightened up almost 12,000 pounds and we started building from there, adding aluminum skid plates, the roll cage, etc.”

Bill says they’d originally planned to just do a motor swap, but during testing the build evolved into what it is today. “We didn’t like where the motor was going to sit in the chassis originally, so we tried just turning the body around on the chassis and set it,” he says. “That put the motor exactly where we wanted it – right where it would be on a hot rod. But I didn’t want to be goofy and drive this thing around backwards, so we needed a solution so we didn’t have to drive it with the transmission in reverse and just cook it.”

Major Payne's drop-on body after paint and some faux patina work.

So Bill engineered his own solution. “We talked to a machinist down in Oregon about building a reverser box, where it’s just two gears – so the power comes in, and once it hits the one gear it changes direction,” he tells us. “But nobody would build me a custom piece. It’s hard to get these big companies who have their machines doing 2,000-part jobs make me one part.”

Frustrated, he decided to try his hand at building a solution. “I have a plasma cutter,” Bill says. “And I just made a multi-plate system where I cut the one plate out, then the next, and I just stacked them all up to make my own transfer case. I built this thing out of steel and it was heavy as hell. We posted something about it on Facebook and somebody made a comment to a friend saying, “Hey Chris, you probably could have made that on your CNC.” This guy just so happened to be a mile down the road with a CNC machine in his garage. I took my design to him and he put it into the computer to make it 3D, and he made me the aluminum transfer case.”

Major Payne poised for its first test session with the new engine combination.

With that issue solved, the project was full steam ahead. “With that we were able to take out the Allison transmission and put in a smaller Powerglide in it,” he says. Motivation for the tank comes from a supercharged, alcohol-fed 540ci Dart power plant that’s outfitted with JE pistons, AFR cylinder heads, and a Weiand 8-71 blower. “It’s around 1100 to 1200 horsepower,” Bill notes.

“The reason why we use JE pistons is because everybody knows building projects is time consuming,” he adds. “The last thing I want to have to do is spend my time trying to put clay in there and trying to figure out what size custom this and that we need. JE has done all of that science for us. They know what every chamber of an AFR head or a Dart head is, they know the stroke, distance, rod length, etc., so you can just call them and say, “Hey, this is what we’ve got and we want to achieve such and such compression,” and they punch in the info and boom, they have what we need. Now I can spend my time working on the other stuff.”